I tend to enjoy acid base titrations for several reasons. First, students get to work with burettes, acids, bases and they see a nice "color change" when they reach an endpoint. Many times, students who tend to struggle with pen and paper testing excel at the "hands-on" approach. Titrations also dovetail well with stoichiometry which provides a nice review of information closer to the end of the year.
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I really enjoy doing reaction rate lab with my students. I often change them up so that I use a different version or tweak an old version. This can lead to a variety of outcomes. Sometimes trying something new or tweaking something that went well before can go wrong.
The answer may be in the anecdotal evidence. The conversations between students were mini debates. “Are you sure this is correct?” “How do you know?” “What about this other data?” “Should we label that number?” “What about the energy of the particles during a phase change?” And on, and on, and on….They were having discussions between themselves that I would not have been able to elicit as a teacher.
My students and I tend to have good experiences with a hydrate inquiry lab that I have "tweaked" (see the previous blog). Essentially, my students have some practice with hydrates in the lab and then they are provided an unknown hydrate. They must separate off the water by heating and calculate the mass of the anhydrous salt and container before they come up and put it on the scale. As an added twist, they must also ask me a question about what information they need from me to calculate the mole to mole ratio of the salt to water.
Formative assessment can be a double edged sword. It can be and often is extremely helpful. Some quick short three or four well worded questions at the beginning of a unit provides information about student abilities. A teacher can skip teaching information that kids already know or the teacher can discover concepts that he or she assumed students know but do not. Formative assessment about "Moles" can provide data that is hard to deal with. Can the students handle scientific notation? How well are students at basic math skills?
Every LED light has a "band gap". Electrons are pushed into an empty orbital which is negative and then the positive end of the circuit attracts the electrons. As they go down in energy through the band gap, they emit light. The larger the band gap, the more energy, the smaller the wavelength and the closer to the "blue" end of the spectrum. So, the key is to try to control the band gap and thus control the color of light.
Card sorts are a great way to achieve a number of classroom objectives. They can be used as a review activity or they can be done during the middle of a lesson as a type of formative assessment. Sorts can encourage students to work with other students or can even be used as a type of exit ticket. I decided to use the strategy about two thirds of the way through a unit on covalent and ionic compounds and lewis structures. I knew there were items we did not cover in the sort but I was curious to see how they would approach these unknown topics.
There are many places online to build a DIY Hoffman apparatus. The ACS offers an electrolysis of water lesson that includes a hand made Hoffman apparatus(link is external) as part of a unit on energy that I used as a resource.